The invention relates to a liquid-cooled choke comprising a choke core, a choke coil and a path for a cooling liquid to cool the choke.
Heat losses occur both in the choke core and the choke coil. This heat should be transferred efficiently to the cooling liquid so that the choke would not be heated too much but would remain in the optimal operating temperature range defined for it.
U.S. Pat. No. 1,790,906 discloses a known solution where a two-piece coil is encapsulated such that a cooling liquid is circulated between the adjacent coils and on their edges in water channels arranged in the middle and ends of the encapsulation. Considering the basic structure of the choke, the implementation is relatively complex, and only the coil will be cooled in this way.
Another, newer arrangement is disclosed, for instance, in EP Patent 459326 where cooling liquid channels are arranged between different layers of the coil in the cast-resin body of the coil. Also this structure is very difficult to implement and it does not take the cooling demand of the core into account.
Typical of the former structures is that the cooling is in one way or another implemented in connection with the coil. These implementations also make the assembly and structure of the choke difficult and complex.